Dremel makes a variety of hand-held rotary tools for grinding, sanding, polishing and routing. Dremel tools are good for small intricate work. However, other individual and combo power tools from other manufacturers, as well as various hand tools, can serve as alternatives to a Dremel tool. The alternative you choose to use is largely a matter of personal preference and the requirements of the task at hand.
From sandpaper taped around a drill bit to a circular metal file, grinding and polishing can be undertaken with hand tools. Sanding blocks with metal sandpaper can both sand and polish objects, albeit with more effort than a Dremel or other power tool requires.
Corded Power Tools
Try other corded power tools. Power drills can offer similar rotary functions. Routers have more power and are generally more durable than a Dremel tool, being designed for heavier duty grinding and cutting jobs. Jigsaws are fine for small case modifications. As with any power tool, higher cost usually means better performance..
Cordless Power Tools
Rohbi cordless for light jobs, a Black & Decker Wizard for complete Dremel accessories compatibility or a cordless Lidl for larger jobs are all variable speed, high-torque rotary tool alternatives for a lesser cost than one Dremel tool.
The blades of a Dremel tool are not meant for large volume jobs. For cutting lots of wood, a Milwaukee Sawzall is a better choice. For lots of drywall cutting, a Bosch Rotozip spiral saw is a more vigorous version of a Dremel. As a general rule, if there is a speciality tool available, use it for durability and performance in place of a Dremel Multi-Max, for instance.